The present invention is directed toward a theft protection system for an electrical instrument and more particularly toward such a system which includes a metal jacketed power cord with a plug at each end which are locked to the instrument and to the electrical wall outlet or other source of power.
In recent years, there has been a marked increase in the theft of expensive electrical laboratory apparatus such as balances, measuring apparatus and the like. These devices utilize standard electrical power cords which are plugged into an electrical wall outlet or a strip of outlets which may be mounted on a workbench or the like. Thieves simply unplug the power cord from the wall and walk out with the entire device including the power cord.
One attempted solution to the problem has been to bolt or otherwise permanently affix the apparatus to the workbench or laboratory table. While this has been of some benefit, it has not been widely adapted since it is inconvenient to have the piece of apparatus bolted or fixed in a particular location. It is often desirable to move the piece of apparatus from one place to another within a laboratory.
It has also been suggested to provide a housing around the electrical outlet which housing has a locking cover so that the plug from the electrical apparatus cannot be removed from the electrical outlet without unlocking the housing cover. Examples of such locking assemblies for electrical outlets are shown in U.S. Pat. Nos. 2,709,198; 3,200,989; 3,293,588 and 4,479,688. Such locking devices may have a slight deterrent effect but would not prevent the theft of relatively expensive laboratory apparatus. Such apparatus normally includes a plug at both ends of the power cord so that the plug at the apparatus itself could simply be unplugged by the thief or, utilizing a pair of wire cutters, he could simply cut the power cord and replace the same after stealing the apparatus.